The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Power transmission devices can include clutch devices connected to rotating coaxial members to transfer torque, e.g., between an internal combustion engine, torque machines, planetary gears, and driveline components of a hybrid powertrain system. One element of a clutch device can include an outer clutch plate having a plurality of inwardly-oriented splines and keys that can engage corresponding keys and splines of an inner clutch plate of a torque-transmitting member. The inner and outer clutch plates engage by applying a thrust force, i.e., a compressive load between the inner and outer reaction plates. Each spline and key of the outer clutch plate and corresponding key and spline of the inner clutch plate has a predetermined amount of lash.
When there is a torque change that causes torque to be applied in the transmission, e.g., during a tip-in event or during a braking event that includes regenerative braking, there can be a change in rotational direction of the devices connected to one of the clutch plates. The splines of the inner clutch plate translate across the lash zone of the key and contact the splines of the outer clutch plate on the opposite side of the key. The impact of the splines on the outer clutch plate can generate an audible noise that is discernible to a vehicle operator, referred to as a driveline clunk.
Known methods for addressing and reducing audible driveline noise during torque transitions include machining splines and keyway surfaces to reduce impact energy, which adds manufacturing process steps.